Microtomes/knives
Cryosectioning
MISC
Common Artifacts
Picture This?
100
Used fo cutting 0.5um plastic sections for light microscopic orientation
What is an ultramicrotome
100
A refrigerated chamber containing a Rotary type microtome
What is a cryostat
100
must be 2-4 degrees above the melting point of paraffin
What is slide warmer
100
This most often results from excessive dehydration of the tissue during the processing step, but may also reslut from a dull blade, too much blade tilt, or cutting too rapidly. Soaking the faced block in icy water to moisten the tissue will help correct this problem if caused by overdehydration.
What is chatter or Microvibration
100
While viewing some slides microscopically the technician notices some white spots possibly caused by too little time in the xylene or by water left in the tissue from incomplete drying
What is incomplete deparaffinization
200
The block is held stationary and the knife is moved along a horizontal plane past the block face
What is a sliding microtome
200
OCT
What is embedding medium
200
Is the optimum temperature of the water bath when sectioning tissue
What is 5-10 degrees below the melting point of paraffin
200
A dull blade, a blade gummed with paraffin, paraffin sticking in the back side of the holder, too little blade tilt, too rapid cutting, or block or room that is too warm will cause this microtomy artifact.
What are compressed, wrinkled, or jammed sections.
200
Sections of paraffin embedded tissue show straight lines running in different angles after the technician used quick freeze spray to chill the block
What are fissures
300
Knife Tilt in relation to the block when cutting sections and approximately 3-8 degrees
What is the clearance angle
300
This will allow water present in the tissue to form ice crystals throughout the specimen
What is slow freezing of the tissue
300
Slides may be coated in this ( a mixture of egg white and glycerine, with an elmer's glue derivative, or with poly-L- Lysine
What is Albumin
300
This may result when tissue that has been improperly processed is floated on the floation bath, or when the flotation bath is too hot.
What is Parched earth
300
Failure to properly do this task will directly result in numerous water droplets to be seen all over the tissue slides upon microscopic evaluation
What is incomplete dehydration
400
A microtome knife has an angle of 15-18
What is wedge angle
400
Optimum temperature for cryosectioning
What -20 degrees celcius
400
As a general guide to cutting good paraffin sections the fly wheel should be rotated at this optimum speed even though each tissue type has an optimum cutting speed that is dependent on the nature of the material, the cutting edge, the angle of the blade, and the thickness of the section desired.
What is one revolution per second
400
These are caused by a major vibration as a result from the block or blade not being tightly clamped in the microtome. They are often seen more frequently with very hard tissue such as uterus.
What is washboarding and or undulations
400
Granular brown stippling resembling pigment or glossy black nuclei can be seen on sections that are allowed to air-dry before mounting
What is cornflaking
500
These have replaced knives in many laboratories
What are disposable blades
500
Rarely used alone for freezing because gas bubbles form around the tissue and impedes freezing
What is liquid nitrogen
500
These extraneous artifacts can be picked up from the flotation bath and are subsequently stained with eosin in a routine H&E stain.
What are sqaumous cells
500
This artifact can be seen microscopically on an H&E stained section and is caused by drying undrained slides at temperatures that are too high
What is nuclear bubbling
500
Any of these will result in retracting mounting medium
What is a warped slide or diluted mounting medium
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